1. Field of the Invention
This invention relates to the field of electrical connectors, and in particular to a capacitive filtering arrangement for an electrical connector.
2. Description of Related Art
A practical arrangement for utilizing chip capacitors in multiple-pin electrical connectors in order to provide filtering of high frequency transients was first proposed in U.S. Pat. No. 4,500,159 (Briones). Previous capacitive filtering arrangements had required relatively expensive monolithic capacitor filters or individual filter sleeves for each contact. In contrast, the Briones connector relies on a completely different structure, based on an insert having a plurality of contact passages and a plurality of recesses in communication with the contact passages, the recesses permitting individual chip capacitors to be inserted such that one electrode on each capacitor engage a respective one of the signal contacts, in order to establish an electrical connection therewith. Connection to ground in the Briones connector is provided by a ground member or clip which also serves to resiliently bias the chip capacitors against the contacts, thus avoiding the need for soldering of the filters to the contacts. Resilient fingers on the clip engage the second electrode on each of the capacitors to provide both the electrical connection and the bias. A second embodiment described in the Briones patent varies this arrangement providing the biasing fingers on the contacts themselves.
The basic Briones design has since been adapted for a variety of purposes other than the original multi-pin filter connectors specifically disclosed in the Briones patent. Examples of subsequent adaptations of the basic Briones design are found, for example, in U.S. Pat. Nos. 4,884,982 (Fleming) and 4,929,196 (Pond et al.), 4,934,960 (Capp et al.) and 5,102,354 (Crane et al.).
Despite the advantages of the Briones chip capacitor design, the use of individual filter sleeve designs persists, especially in connectors in which the use of an external ground clip is impractical. These filter sleeve connector designs have in common the use of a grounding plate positioned transversely to the contacts, a pioneering example of which was disclosed in U.S. Pat. No. 3,569,915 to Sorenson. While it would be desirable because of the cost advantages and simplicity of chip capacitor designs to use clip capacitors even in Sorenson type connectors, the combination has heretofore been impossible to implement due to the relatively great structural dissimilarities between external ground clip designs of the type disclosed in Briones and ground plate designs of the type disclosed by Sorenson. The present invention therefore seeks to provide a practical way of utilizing capacitive filter chips in connection with a transversely extending group plate, thus permitting the maximum possible flexibility in grounding designs for filter connectors. The proposed arrangement can be used in a variety of connectors and, in particular, in adapters of various kinds, including those with circular and rectangular cross sections, and in connection with a variety of different contact pin configurations.
The problem of utilizing chip capacitors in connection with a transverse ground plate was previously considered by Yu et al. in U.S. Pat. No. 5,057,041, with less than completely satisfactory results. This patent discloses chip capacitors electrically connected between an electrical contact and spring tines in a ground plate. However, the Yu design requires the live electrode of the capacitor to be positioned in a receptacle means provided on the contact. The need for this relatively complicated structure results from the placement of the capacitors transversely to the principal axes of the contact which increases the required distance between signal contacts and makes it difficult to establish support for the capacitors while at the same time also establishing a secure electrical connection to the ground plate. In contrast, the present invention proposes to place the capacitor chips parallel to the signal contacts, thus decreasing the distance between the contacts while nevertheless providing a secure electrical connection to the ground plate with a simplified structure that eliminates the need for a receptacle means of the type required by the Yu design.
The present invention thus proposes to provide chip capacitors instead of the conventional filter sleeves in an electrical connector having a common ground plate positioned transversely to axes of the contacts, but does so by placing the capacitors in a direction parallel to the contacts, i.e., by arranging capacitors so that their principal axes between the end electrodes are parallel to axes of the contacts, rather than transverse thereto, greatly simplifying both the contact structure and the ground plate structure.